Underhill’s Mysticism identifies five distinct stages through which the mystical life develops as the soul finds its way to union with God: awakening, in which one makes a commitment to seek God with all of the heart; purgation, in which one, realizing one’s own finitude and imperfections, seeks to become detached from all sensible things through discipline and mortification; illumination, in which God gives the soul various “consolations” as encouragement—voices, visions, trances; the dark night of the soul, in which all sense of God’s presence vanishes and the mystic must struggle on toward the goal of faith; and finally union, in which the soul is united with God.
Underhill’s interest in Mysticism is in the philosophical basis for mysticism, an understanding of the universe as constituted on two levels: that of the physical senses and that of the spiritual realm. She does not analyze or critique at any length, however, the Neoplatonism on which most understandings of mysticism have been based. Her interest is more psychological than philosophical or theological. In looking at the psychological aspects of the mystical life, Underhill notes with the anonymous author of The Cloud of Unknowing that “By love [God] may be gotten and holden, but by thought . . . never.” Throughout she stresses the psychological maturity and balance that has characterized the great Christian mystics.